Nassau Democratic county executive candidate Adam Haber has proposed a bi-county summer sports and entertainment festival that would feature local athletes and entertainers and promote regional tourist spots.

"We need to think differently about tourism," said Haber, a Roslyn school board member who is challenging Thomas Suozzi for the Democratic nomination for county executive. "We are grossly underutilizing our assets and leaving so much money on the table."

Haber envisions an annual 10-day festival in early July -- likely beginning in 2015 -- featuring top amateur athletes from across the nation competing in events such as beach volleyball, softball, a three-stage bicycle race, marathons, golf, fishing and cricket.

Events would be held in locations throughout Nassau and Suffolk, and could attract visitors to area beaches, wineries and golf courses to increase revenue.

Haber said the festival could raise "hundreds of millions" of dollars through increased sales taxes, sponsorships, entry fees and television broadcast rights.

The festival, Haber said, would also allow Long Island to compete in a regional tourism competition conceived earlier this year by Gov. Andrew M. Cuomo. The competition encourages counties to develop tourism marketing plans, with the winners sharing $5 million.

Suozzi, who served as Nassau County executive from 2002-2009, did not respond to a request for comment. County Executive Edward Mangano, a Republican who will take on the Democratic nominee, declined to comment, as did Suffolk County Executive Steve Bellone.